CVE-2021-47262

Kernel disclosure and crash via stale tracepoint strings

Published May 21, 2024 · Updated May 11, 2026

Use-after-free in the Linux KVM x86 tracepoint allows local users to disclose kernel memory or crash the host through trace output. The kvm_nested_vmenter_failed tracepoint retains pointers to string literals owned by unloadable kvm-intel or kvm-amd modules instead of copying them. Triggering the condition requires local access, enabled KVM tracing, a recorded nested VM-entry failure, and unloading a vendor module before the trace buffer is read.

CVSS severity7.1
High
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in the Linux KVM x86 tracepoint allows local users to disclose kernel memory or crash the host through trace output. The kvm_nested_vmenter_failed tracepoint retains pointers to string literals owned by unloadable kvm-intel or kvm-amd modules instead of copying them. Triggering the condition requires local access, enabled KVM tracing, a recorded nested VM-entry failure, and unloading a vendor module before the trace buffer is read.

The record

CVE
CVE-2021-47262
Published
May 21, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 21, 2024CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=380e0055bc7e4a5c687436ba3ccebb4667836b95 <796d3bd4ac9316e70c181189318cd2bd98af34bc
  2. Affected versionversion=380e0055bc7e4a5c687436ba3ccebb4667836b95 <9fb088ce13bc3c59a51260207b487db3e556f275
  3. Affected versionversion=380e0055bc7e4a5c687436ba3ccebb4667836b95 <d046f724bbd725a24007b7e52b2d675249870888
  4. Affected versionversion=380e0055bc7e4a5c687436ba3ccebb4667836b95 <f31500b0d437a2464ca5972d8f5439e156b74960
  5. Affected versionversion=5.4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=380e0055bc7e4a5c687436ba3ccebb4667836b95 <796d3bd4ac9316e70c181189318cd2bd98af34bc; version=380e0055bc7e4a5c687436ba3ccebb4667836b95 <9fb088ce13bc3c59a51260207b487db3e556f275; version=380e0055bc7e4a5c687436ba3ccebb4667836b95 <d046f724bbd725a24007b7e52b2d675249870888; version=380e0055bc7e4a5c687436ba3ccebb4667836b95 <f31500b0d437a2464ca5972d8f5439e156b74960; version=5.4

Published CVSS scores

7.1CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
3.3Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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